Background: This study aims to evaluate and compare central foveal thickness (CFT) changes after cataract surgery between normal and diabetic patients without retinopathy, using optical coherence tomography (OCT).Patients and Methods: Ninety-eight patients (49 patients with type 2 diabetes and 49 healthy controls, sex- and age-matched) undergoing phacoemulsification in one eye were included. The presence of retinopathy was an exclusion criterion. The OCT examination was performed preoperatively as well as one, three, six and twelve months postoperatively. CFT was evaluated and compared between groups. Results: Preoperative CFT showed no significant difference between the two groups (normals: 205 ± 18 μm vs. diabetics: 202 ± 23 μm, p > 0.1). Postoperative CFT in diabetics at all time-points of the follow-up period was significantly increased when compared to controls (first month, normals: 215 ± 28 μm vs. diabetics: 262 ± 33 μm, p <0.05; third month, normals: 211 ± 19 μm vs. diabetics: 250 ± 27 μm, p <0.05; sixth month, normals: 208 ± 12 μm vs. diabetics: 266 ± 13 μm, p <0.05; and twelfth month, normals: 209 ± 13 μm vs. diabetics: 280 ± 11 μm, p <0.05). The incidence of cystoid macular edema (CME) was 4.0 % and 28.6 % for the control group and the diabetic group, respectively, at the end of the follow-up period (p <0.05).Conclusion: Eyes of diabetic patients without retinopathy present higher CFT and a higher incidence of CME after cataract surgery on OCT examination compared to eyes of healthy controls. This may explain the unsatisfactory visual acuity following cataract surgery in these patients.